Template-Type: ReDIF-Article 1.0 Author-Name: Z. Hlaváčová Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Title: Low frequency electric properties utilization in agriculture and food treatment Abstract: Determination of electrical properties is utilized in a wide range of disciplines and industries. A brief compendium of agricultural materials and food electrical properties exploitation is presented in this paper. The measurement of electrical conductivity or resistivity can be utilized at investigation of cell membrane properties on microscopic level. Moreover the electrical conductivity have utilization at the salinity of soils and irrigation water determination. Biological material properties are determined from their leachates too. The conductivity measurement are applied for determination of various characteristics of agricultural materials and food, for example for determination of the frost sensitiveness, of chilling and freezing tolerance, of moisture content, of seeds germination, of mechanical stress, of pasteurization, of other properties of grains, seeds, meat, sugar, milk, wood, soil, fruit and vegetable, infected food, … The utilization of dielectric properties are also described; for example in agricultural materials and food quality sensing (moisture content, maturity of fruit, freshness of eggs, potential insect control in seeds, radio frequency heating, …). The classification of permittivity measurement techniques at the low frequencies is mentioned. Keywords: electrical properties, moisture content, resistivity, conductivity, permittivity, impedance Journal: Research in Agricultural Engineering Pages: 125-136 Volume: 49 Issue: 4 Year: 2003 DOI: 10.17221/4963-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4963-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200304-0001.txt Handle: RePEc:caa:jnlrae:v:49:y:2003:i:4:id:4963-RAE Template-Type: ReDIF-Article 1.0 Author-Name: Ľ. Kubík Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Author-Name: A. Pavelková Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Author-Name: T. Hornyák Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Author-Name: P. Kováč Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Author-Name: V. Horčin Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Author-Name: J. Fúsková Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Title: Evaluation of long term storage of apples by means of fractal analysis Abstract: Realization of long-term apple storage requires the most detailed information about the flesh structure and texture, whose quality is contributing by responsible way to the whole quality of the evaluated fruits. The fractal analysis that the fractal dimension of the flesh structure determination is enabling was used. Structure degradation of four apples variants of the variety Idared was evaluated by fractal dimension during long-term storage in standard conditions. The influence of the storage on the fractal dimension was investigated by means of regression dependencies. The dependences express a decrease of the fractal dimension value in the relation to the increasing storage period. The influence of long term storage and influence of the variants of the fertilization on the fractal dimension was confirmed by means of analysis of variance. Connectivity between fractal dimension and descriptors of quality of the apple flesh structure was determined with utilization of the sensoric analysis. Fractal dimension expresses the structural and textural properties of the apple flesh. Keywords: storage, fractal, apples, flesh, structure Journal: Research in Agricultural Engineering Pages: 137-145 Volume: 49 Issue: 4 Year: 2003 DOI: 10.17221/4964-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4964-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200304-0002.txt Handle: RePEc:caa:jnlrae:v:49:y:2003:i:4:id:4964-RAE Template-Type: ReDIF-Article 1.0 Author-Name: J. Lendelová Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Author-Name: Š. Pogran Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Title: Thermo-technical properties of floor structures for lying cubicles Abstract: A paper dealing with prevailing floor construction types from a thermo-technical point of view. The accent was put on lying cubicles for cows, the floors must be soft, dry, warm and flexible. Attention was paid to analysis of the thermal resistance and thermal absorptive capacity of selected types of flooring. The greatest thermal comfort depends upon the design of floor structured coating materials. A biological floor accretion layer has a positive thermal influence and softens thermal comfort during the animals lying period. A calculation, estimating values of thermal absorptive capacity, shows that the quality and thickness of the structured layer on a covered floor is very important, underlying layers are only affected with thinner designs of a calculated boundary value. Keywords: cow, floor, lying cubicle, thermal comfort, thermal absorptive capacity Journal: Research in Agricultural Engineering Pages: 146-150 Volume: 49 Issue: 4 Year: 2003 DOI: 10.17221/4965-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4965-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200304-0003.txt Handle: RePEc:caa:jnlrae:v:49:y:2003:i:4:id:4965-RAE Template-Type: ReDIF-Article 1.0 Author-Name: I. Petranský Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Author-Name: M. Bolla Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Title: Testing stand for life tests of hydrostatic pumps with a polluted fluid Abstract: Testing of the lifetime of hydrostatic transmissions can be done on special testing stands. Some testing stands use a pressure valve connected at the outlet of a pump. When using this design of stands, it is important to keep clear the operating fluid by filters and it is not possible to observe the influence of fluid pollution on the lifetime. The article presents a design of an electro-hydraulic testing stand with computer control system for accelerated lifetime tests of hydrostatic pumps under laboratory conditions when using a polluted operating fluid. A pump, which is mechanically connected with a hydrostatic motor, through a clutch, is an interface between the hydrostatic circuit of the tested pump and the hydrostatic circuit of the loading simulator. At lifetime testing, this interface makes it possible to use the polluted fluid in the hydraulic circuit of the tested pump, and thereby observe its influence. Instead of a polluted fluid, it is possible to use biodegradable oil and observe its influence on the lifetime of a pump. When using the same hydraulic fluid in both systems of the stand, it is possible to test two pumps at the same time. Keywords: hydrostatic transmission, hydraulic oil PP 80, simulator of dynamic loading Journal: Research in Agricultural Engineering Pages: 151-156 Volume: 49 Issue: 4 Year: 2003 DOI: 10.17221/4966-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4966-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200304-0004.txt Handle: RePEc:caa:jnlrae:v:49:y:2003:i:4:id:4966-RAE Template-Type: ReDIF-Article 1.0 Author-Name: M. Božiková Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Title: Thermophysical parameters of corn and wheat flour Abstract: This article deals with thermophysical properties of nutritive raw materials particularly of corn and wheat granary mass. It is necessary to know thermophysical performance of granary mass for protection of quality of technological process by processing to final products. Granary mass consist of grains complex of specific kind. It is non uniform material in microscopic and macroscopic structure. There are enacted biophysical and physiological processes. Heat transfer can not be isolated by solid transfer and heat - moisture transfer. It means that specification of granary mass and granary fragments is difficult to determine. We researched thermal properties of fragments of corn and wheat grain, concretely corn and wheat flour. In the first series of measurements we measured relations of thermal conductivity to the moisture content in range (2/18) % for two different samples - corn flour and wheat flour. Function f ( to bulk density S, samples had identical moisture content 6.5%. For size of corn and wheat grains in range (0.063/0.5) mm this is polynomical function. Measured results are corresponding with results at present literature (Ginzburg et al. 1985). Keywords: thermal conductivity, thermal diffusivity, moisture content, bulk density Journal: Research in Agricultural Engineering Pages: 157-160 Volume: 49 Issue: 4 Year: 2003 DOI: 10.17221/4967-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4967-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200304-0005.txt Handle: RePEc:caa:jnlrae:v:49:y:2003:i:4:id:4967-RAE Template-Type: ReDIF-Article 1.0 Author-Name: J. Bajla Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Author-Name: Z. Balogh Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Author-Name: M. Božik Author-Workplace-Name: Slovak University of Agriculture, Nitra, Slovak Republic Title: Exploitation of the software product Pro/Mechanica in the agricultural research Abstract: The program system Pro/MechaniCa is a specific software product designed for solving of different kinds of technical problems in general engineering. We were looking for usage not only in the engineering but also in the terramechanical area. We realized a simulation loading of the soil with a rigid circular table and after the loading we calculated deformations and stresses under the table using FEM (Finite Element Method). This article shows a specific exploitation program Pro/Mechanica in an unconventional area as well as in the agricultural area. Keywords: program product, FEM (Finite Element Method), Pro/Mechanica, deformation and stress of soil, modelling Journal: Research in Agricultural Engineering Pages: 161-164 Volume: 49 Issue: 4 Year: 2003 DOI: 10.17221/4968-RAE File-URL: http://rae.agriculturejournals.cz/doi/10.17221/4968-RAE.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/rae-200304-0006.txt Handle: RePEc:caa:jnlrae:v:49:y:2003:i:4:id:4968-RAE